Automatic welding machines which are used for the orbital welding of large-size components of rotational symmetry, such as pipes, are known in the art.
To prolong the lifetime of pressurized-water nuclear reactors, it has been proposed to carry out the complete change of the steam generators which, during operation, experience wear attributable to corrosion caused by the primary water and by the feed water. The steam generators are connected to the primary pipelines in the region of their water boxes, and, after a new replacement generator has been installed, it is necessary to carry out the butt welding of the primary pipelines and the connection pieces of the water box. These operations are carried out on the primary circuit of a nuclear reactor which has already been in operation, and therefore in a highly radioactive environment. An automatic remote-controlled welding machine consequently must be used in order to carry out the connecting welding of the replacement steam generator. A remote-controlled orbital TIG welding machine is generally used for this operation, the entire welding operation being computer-assisted. The control station is usually at a great distance from the zone where welding is carried out, and various connections between the welding machine and the control station are required, for example in order to control, regulate and display the welding operation.
The orbital welding machine comprises a head moving on a rail arranged round the pipe and the connection piece to be joined by welding. The welding head must to be connected to the control station by means of an assembly of feeder and signal transmission cables, making it possible to supply the electrical current necessary for carrying out welding, setting the various welding parameters and controlling the movements of the electrode. The feeder and signal transmission cables are bulky and heavy and must follow the orbital movement of the welding head, without thereby causing disruptions to the welding in progress. The cables are therefore usually installed in two flexible large-diameter tubes called umbilicals, so that it is possible to carry out the guidance and combined handling of the various cables connected to the welding head.
To date, there has been no known apparatus making it possible to carry out in the most efficient possible way the guidance, storage and handling of the cables connected to the welding head.